Turning AI Into a Daily Habit: How CMS Reached 95% Adoption With Harvey

Key Highlights

• 95% adoption across 3,000+ lawyers during the initial rollout
• Scaled firmwide to 7,200 lawyers across 50+ countries — one of the world’s largest GenAI deployments in legal
• Lawyers review larger document sets faster, unlocking new types of work
• AI is now a daily habit, shaping how CMS delivers value to clients

About CMS

CMS is one of the world’s largest international law firms, with 7,200 lawyers and more than 10,000 professionals across over 50 countries. Known for its forward-looking approach to legal services, the firm continually invests in technology that helps lawyers deliver better outcomes for clients operating in complex global markets.

As generative AI began reshaping professional services, CMS moved quickly to explore how it could enhance legal work. The firm partnered with Harvey to bring legal-specific AI capabilities directly into lawyers’ daily workflows — helping them analyze documents faster, surface insights from large knowledge sources, and produce stronger first drafts.

What began as a focused pilot quickly became one of the most successful technology rollouts in the firm’s history.

Opportunity

CMS leadership recognized early that generative AI would fundamentally reshape how lawyers work — and that realizing its potential would require more than simply giving lawyers access to a new tool.

Equally important was understanding how the technology could be applied in practice.

“Our clients have access to these tools as well,” said Craske. “If we don’t understand what they can do — and how to apply them — we’re not even in the race.”

CMS evaluated several generative AI platforms before selecting Harvey. Its legal-specific capabilities, rapid product development, and ability to support real legal workflows set it apart.

Security was also critical.

“Our clients give us extremely sensitive data,” said Bert Vries, Head of Innovation, Knowledge & Technology at CMS Netherlands. “We needed a partner that could demonstrate the highest standards of security and governance.”

With the right platform in place, CMS focused on the most important challenge: adoption.

Solution

CMS approached implementation as a transformation program — not a simple technology rollout.

The Legal Tech and Innovation teams, led by Laura Fessey, Head of Legal Tech at CMS, and Bert Vries, Head of Innovation, Knowledge & Technology at CMS Netherlands, launched an initial trial followed by a twelve-month pilot with 300 lawyers across multiple practice areas.

Lawyers tested Harvey on real matters — reviewing contracts, summarizing documents, and extracting insights from curated knowledge sources.

Fessey’s team focused on practical enablement: onboarding lawyers, sharing real use cases, and embedding the platform into live matters.

“We’re responsible for piloting new tools and helping lawyers adopt them in real work,” said Fessey. “Once people see what Harvey can do, it helps them become more effective.”

Adoption spread quickly across jurisdictions and practice groups. Lawyers began sharing their own examples of how Harvey accelerated document analysis, streamlined research, and improved drafting. Those stories created momentum across the firm.

By the summer of 2025, CMS had more than 3,000 lawyers using Harvey — and over 95% of them were active users. At that point, the decision was clear: scale Harvey across the firm.

Today, CMS lawyers use Harvey across a wide range of workflows:

• Contract Review and Issue Spotting: Teams analyze agreements and generate structured issue lists that highlight key risks and negotiation points.
• Knowledge Synthesis: Lawyers surface insights from curated legal materials in seconds rather than hours.
• Large-Scale Document Analysis: Teams review significantly larger document sets across complex matters and jurisdictions.

“With Harvey, we can review much larger document sets much faster than before,” said Fessey. “It enables us to take on different types of work that previously wouldn’t have been possible.”

For many lawyers, Harvey quickly became indispensable.

“I’m always surprised by how many places Harvey is useful,” said Vries. “It’s like a Swiss Army knife — there are so many use cases.”

Impact

CMS’s adoption of generative AI has delivered both measurable efficiency gains and meaningful cultural change.

Lawyers save significant time on routine tasks, allowing them to focus on higher-value analysis, strategy, and client work.

“We see happier lawyers,” said Vries. “Because we’re saving time, we can spend more time on value-added activities.”

Harvey has also expanded what CMS lawyers can do for clients. Teams can analyze larger volumes of documents, surface insights faster, and deliver higher-quality advice under tight timelines. In many cases, lawyers can now take on work that previously would have been impractical due to time constraints.

Clients have taken notice. CMS lawyers regularly discuss their use of Harvey with clients — sharing examples of how AI enhances legal services and enables new types of work.

“Hearing the stories of how lawyers use Harvey — and sharing those stories with clients — creates its own return,” said Craske.

For CMS, generative AI is no longer an experiment. It is becoming a core part of how the firm practices law.

“AI isn’t optional anymore,” said Fessey. “It’s an expectation. The real question is how you apply it.”